Method of treating a tow of filaments or threads



y 1951 R. H. K. THOMSON ET AL 5, 65

METHOD OF TREATING A TOW OF FILAMENTS 0R THREADS Filed Jan. 14, 1948 2Sheets-Sheet 1 M 10 g 1 6 It l mi aMMm

y 1951 R. H. K. THOMSON ET AL 6 METHOD OF TREATING A TOW 0F FILAMENTS ORTHREADS Filed Jan. 14, 1948 v 2 Sheets-Sheet 2 I N V EN TORS Rolar'nJzizmr'zima Jfndall Thomsfln, Mi i2 16am Edwazfl flei'zogw, 1y

Patented May 29, 1951 METHOD OF TREATING A TOW O F FILAMENTS OR THREADSI Robin H. K. Thomson, Largs, William E. Tetlow,

Saltcoats, and Archibald McDonald, Kilassignors' to Imperial Limited, acorporation of marnock, I Chemical Industries Great Britain Scotland,

Application January 14, 1948, Serial No. 2,246 In Great Britain March19, 1947 4 Claims. (o 8-1512) The present invention relates to a methodof treating atow of filaments or threads in a limited space.

In the manufacture of filaments or threads it frequently happens thatthefilaments or threads have to be submitted for an appreciable periodoftime to one ormore operations of wet or dry processing. It is desirableto carryout the manufacture of said artificial filaments or threads inas continuous a manner as possible, but as the different operationsincluded in the manufacture may take differing periods of time tocomplete, some of them appreciable periods, much space and largequantities of reagents may be required if they are to be carried out ona continuously advancing tow offilaments or threads.

The object of the present invention is to proyidea simple, and eflicientmethod of treating under non-tensioning conditions a continuoustrayelling tow of filaments or threads by immersion in a treatingliquid, particularly one having a specific gravity approaching that ofsaid tow, for relatively long periods of time.

'It is known to be impracticable to allow a continuous travelling tow offilaments or threads tofall into and accumulate or form folds in aitreating-liquid contained in a static tank of large but reasonabledimensions. entangled if a sufiicient length is permitted to accumulatein the tank for it to receive the necessary time of treatment in thetreating liquid.

The tow becomes Unsatisfactory results arealso obtained if a tow foffilaments or threads is permitted to drop into and to form folds in aliquid, particularly onerhaving a specific gravity approaching that 'ofsaid tow, flowing through a static trough as tangling again results,presumably due to those portions of the folds in the centre of thetrough moving faster than those nearer to the walls 'of the trough for,to consider .any one horizontal plane of the liquid only, as is wellknown, the

velocity of the liquid in contact with the walls of a stationary troughapproaches zero while the tially with a velocity equal to the meanvelocity of the liquid therein will be substantially free from theVarious velocity gradients which occur in a liquid flowing in astationary trough it should be possible to permit a tow of filaments orthreads itofallg nto. and to form folds in a liquid conliquid at tainedin such a moving trough without tangling taking place as the treated towis removed from the liquid.

According to the present invention the method of treating a continuoustow of filaments by immersion in a treating liquid for a relatively longperiod of time. comprises providing a hori- -zohtal ring-troughrotatable about a vertical axis, passing treating liquid in a continuousmanner through said ring-trough and rotating, the ring-trough withsubstantially the same directional speed as the mean circular velocityattained by the said treating liquid in said ringtrough, inducing avibratory motion substantially radial to the centre of the rotatingring-trough in thetow directly above the treating liquid, per- 1 mittingthe thus treated tow to fall into the treating liquid and to form itselftherein into, folds on the floor of the rotatingtrough below the regionimmediately above the 1iquid from which the tow enters the liquid andalso regulating the speed of rotation of the ring-trough so that onwithdrawing the tow from out of the treating liquid at any desireddistance away from the said region measured along the circumference ofthe ringetrough the said tow has remained in the treating liquid for thedesired period of time.

' r If desired the tow can be given the said vibratory motion by passingit through a guide positioned vertically above the treating liquid andhaving a reciprocating movement radial to the centre of the rotatingring-trough.

It is essential in order to carry out the invention successfully thatthe tow undergoing treatment should be of greater density than that ofthe treating liquid in the rotatingring-trough. It sometimes ,becomesnecessary therefore to give the tow a preliminary treatment before it ispermitted to enter a particulartreating liquid in a rotating ring-troughto make the tow of greater density than that of the treating liquid.

For example, the tow may be immersed in a bath containing a particulartreating liquid of a rotating ring-trough before it is allowed to enterthe said treating liquid in arotating ring-trough.

The tow of filaments or threads, if desired, can

'be passed from a treating-liquid contained in 3 ring-troughs can bearranged concentric to one another.

In one embodiment of the invention the rotatable ring-trough has aperforated base and is partly immersed in a larger and static troughwhich is provided with means for maintaining a constant level of liquidtherein. The ring-trough is supplied continuously with treating-liquiddelivered at such a rate as to make up for that which leaves it bypassing through the perforations at its base. The treating-liquid isdelivered from above and preferably close to the inner wall of thering-trough. The one or more points of delivery of the treating-liquidare not connected with the ring-trough. By delivering the treatingliquid in this way as for example radially from the centre of the troughany tendency towards crystallisation of the treating-liquid is lessenedand the possibility of maintaining the treating-liquid at a constantpredetermined high temperature throughout the treatment of the tow isincreased.

In accordance with another embodiment of the invention thetreating-liquid is pumped in and out of the rotating ring-trough at sucha rate that the liquid is substantially static i. e. without relativemotion, with respect to the rotating ringtrough. It may be desirable toprovide one or more baffles between the inlet and outlet devicesprovided for the treating-liquid in the ringtrough.

The invention is illustrated by the following example in which parts areparts by weight except where otherwise stated and with reference to theaccompanying diagrammatic drawings in which Fig. 1 is a front elevationof apparatus suitable for carrying out the method of the invention, Fig.2 is a side elevation in direction of arrow A in Fig. 1, Fig. 3 is aplan, Fig. 4 is a section of that part of the apparatus in which the towis treated in the first ring-trough and Fig. 5 is a section of that partof the apparatus in which the tow is treated in the second ringtrough.

Example A matured caustic soda solution of groundnut globulin preparedfrom a solution containing 25 parts peanut globulin, 1.25 parts sodiumhydroxide, 1.0'part sodium sulphite and 72.75 parts water is extrudedinto a coagulating bath containing 200 gm./1 sodium sulphate and 20gm./1 sulphuric acid. The resulting tow of filaments is taken up ongodets having a peripheral speed of 30 metres per minute and stretchedby passing on to godets having a peripheral speed of 45 metres perminute.

The tow I is then led under tension to a godet 2 situated verticallyabove the'centre line of the trough of a ring-trough 3, through areciprocating spacing device 4 at least 3 feet above the surface of theliquor in the trough 3, and so into the trough in which the fibre isdeposited in a zig-zag manner. This ring-trough 3 consists of a solidcentre section 2 feet in diameter with a trough 6 inches wide and 3inches deep outside but integrally joined to it and is made of mildsteel. This unit has a base of wire gauze 5 and revolves in a circulartrough 6 3 feet 4 inches external diameter, 1 foot 7 inches internaldiameter and 6 inches deep, also of mild steel fitted with an adjustableweir I so that the height of liquor in the trough may be varied at will.A solution of sodium sulphate, saturated at C. is run through a pipe 8to the centre of the centre section of the ring-trough at 15 C.

and spreads out to enter the revolving trough at a multiplicity ofpoints. The tow sinks on to the wire gauze base 5 of the trough and iscarried round with the trough which revolves once every 7 minutes. Thusthe time of immersion of the tow in the treating-liquid can be 7%minutes. The tow is taken up not less than 3 inches from the fibre inletand then stretched between two godets (9 and I0) Whose peripheral speedsare 35 and 52 metres per minute respectively.

After stretching, the tow passes over a godet II placed vertically abovethe centre line of the outer trough of a ring-trough consisting of twoconcentric troughs (I2 and I3), each 6 inches wide by 4 inches deep. Theoutside diameter of the outer trough I2 is 4 feet and the insidediameter of the inside trough I3 is 2 feet. This ringtrough is made ofmild steel and is lead lined. The tow enters the outer trough I2 in azig-zag manner through a reciprocating spacing device I4 placed at least3 feet above the liquid level in the trough. The treating liquor at 50C., which consists of a solution of sodium sulphate saturated at 60 C.containing 1%% formaldehyde at pH 5 enters the outer trough I2 through adistributing pipe I5 5 /2 inches long which is arranged along a diameterof the trough and at least 6 inches from the fibre inlet, and is removedby a constant level automatic syphon I6 drawing from the space betweenthe fibre inlet and outlet. The rate of rotation of the ringtrough isonce in ten minutes and hence the time of immersion in thetreating-liquid can be 10 minutes. The tow is picked up over a godet l'Iarranged so that the fibre line coincides with a diameter of the troughand that the distance between the fibre inlet and take up is at least 8inches. The tow is stretched 50 per cent between the two godets (I1 andI8) whose peripheral speeds are 43 and 62 metres/minute, while the towis immersed in a small rectangular trough I9 2 feet long, 9 inches deep,3 inches wide. The liquor used in the trough I9 is the same as that usedin the inner trough I3 and. is at 90 C.

The tow enters the inner trough I3 in a zig-zag manner over the godet I8placed over the centre line of the inner trough I3 and through areciprocating spacing device 20 at least 3 feet above the liquid levelin the trough. The treatingliquor inlet 2| is by means of four pipes atright angles feeding to the inner wall of the trough I3. Thetreating-liquor, sodium sulphate saturated at C., containing 1formaldehyde and 20% sulphuric acid by volume, is removed by a constantlevel automatic syphon 22 drawing from the space between the fibre inletand take up. The temperature of the treating-liquor is 70 C. The tow istaken up over a godet 23 at least 8 inches from the inlet and washed anddried by any known method.

We claim:

1. A method for treating without tangling a continuous tow of artificialwet spun protein filaments by immersion thereof in a treating liquid fora relatively long period of time, said method comprising the steps ofcontinuously flowing the treating liquid through the trough portion of ahorizontally disposed, rotatable ring trough, rotating said trough in ahorizontal plane about its central axis at substantially the samevelocity as the mean circular velocity attained by said treating liquidso that said treating liquid and trough are substantially free fromvelocity gradients with respect to each other, depositing said tow insaid ring trough radially thereof 5 6 and in a zig-zag manner, andwithdrawing the thus treated tow after the desired period of REFERENCESCITED treatment h s e p The following references are of record in the 2.The method of clalm 1 wherein said art1- fil of this t t;

ficial wet spun filaments are obtained from pea- 5 nut proteins. UNITEDSTATES PATENTS 3. The method of claim 1 wherein said treat- Number NameDate ing liquid has a greater density than said tow, the 9, V011Recklinghausen latter being given a preliminary treatment et a1. Mar 7,1939 whereby its density is rendered greater than that 10 2,251,931Gundelfinger A 1941 of said treating liquid.

4. The method of claim 1 wherein said tow is FOREIGN PATENTSsuccessively deposited in first one ring trough Number fflt Date andthen another, said troughs being concentric 475,350 Great Brltam 1937 toone another. 15

ROBIN H. K. THOMSON. WILLIAM E. TETLOW. ARCHIE M. MCDONALD.

1. A METHOD FOR TREATING WITHOUT TANGLING A CONTINOUS TOW OF ARTIFICIALWET SPUN PROTEIN FILAMENTS BY IMMERSION THEREOF IN A TREATING LIQUID FORA RELATIVELY LONG PERIOD OF TIME, SAID METHOD COMPRISING THE STEPSCONTINUOUSLY FLOWING THE TREATING LIQUID THROUGH THE TROUGH PORTION OF AHORIZONTALLY DISPOSED, ROTATABLE RING TROUGH, ROTATING SAID TROUGH IN AHORIZONTAL PLANE ABOUT ITS CENTRAL AXIS AT SUBSTANTIALLY THE SAMEVELOCITY AS THE MEANS CIRCULAR VELOCITY ATTAINED BY SAID TREATING LIQUIDSO THAT SAID TREATING LIQUID AND TROUGH ARE SUBSTANTIALLY FREE FROMVELOCITY GRADIENTS WITH RESPECT TO EACH OTHER, DEPOSITING SAID TOW INSAID RING TROUGH RADIALLY THEREOF AND IN A ZIG-ZAG MANNER, ANDWITHDRAWING THE THUS TREATED TOW AFTER THE DESIRED PERIOD OF TREATMENTHAS ELAPSED.